Simple Definition:

A preposition is a word that shows the relationship between two things in a sentence. It indicates location, direction, time, or manner.

Examples:

• The cat is under the table. (Under shows the location of the cat in relation to the table.)
• She walked towards the park. (Towards shows the direction of her walk.)
• I will meet you at 3 p.m. (At shows the time of the meeting.)
• They ran quickly to catch the bus. (Quickly shows the manner in which they ran.)

Very Simple Definition:

A preposition is a word that shows the relationship between two things, such as an action and a time, or an object and a location.

Examples:

• The cat is under the table.
• She walked towards the park.
• I will meet you at 3 p.m.
• They ran quickly to catch the bus.